But despite extending their lead at the summit, Ferguson was far from happy with his side's performance, as twice they were forced to come from behind against the Royals, who find themselves in the bottom three.

United's victory was their seventh after falling behind this season and Ferguson is becoming increasingly frustrated by his side's defence, saying his side "deserved to be battered".

"I thought it might be a record Premier League score at half-time," Ferguson told ESPN. "It was really, really bad defending. That was the absolute worst it's been this season. We deserved to get battered today. We scored goals thankfully which rescued us.

"If you make mistakes like that defending then you are going to have to do rescue jobs every week. Today was another rescue job. It was a miracle that we won the way we were defending. I'm just glad we did win it."

Speaking about his decision to substitute Rafael, who looked less than impressed as he walked to the bench, Ferguson added: "I brought Chris Smalling on, which was an improvement in terms of height. The boy was disappointed coming off. He has been one of our best players this season.''

Rooney labelled United's first-half display as "crazy'' but believes the character of the team ensured they secured a win that moved them three points clear of Manchester City ahead of next weekend's derby.

"It was crazy to be honest but we dug in there,'' he said. "We knew that in the first half our defending from set-pieces wasn't good enough and that can cost us. In the second half we wanted to be more solid. We were happy to get the three points.''

Asked what was said at half-time, he added: "Just to defend better, to stay with our runners and get against our players at set-pieces. In the second half we did that.''